Electric switch



Oct. 28, 1941. B. HINKS 2,260,901

ELECTRIC swn-cn Filed Dec. 14, 1939 5 Sheets-Sheet l :F an IN ENFOR- Q11 TTORNEYS- Oct. 28, 1941. B. HINKS 2,260,901

ELECTRIC SWITCH Filed Dec. 14,,1939 5 Sheets-Sheet 2 5]1 a 29 I6 I25 4%5 lll/VEIVTOR.

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Oct. 28, 1941. B. HINKS ELECTRIC SWITCH Filed Dec. 14, 1939 5Sheets-Sheet 3 E A 5/ m KL 5 L w 6 0 ,5 MM 2 2 M m \k K M5 M 5 2 5 5 '45 5R 2% Hinks MmE/wvR.

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Oct. 28, 1941. B, Hl NKS 2,260,901

ELECTRIC SWITCH Filed Dec. 14, 1959 4 5 Sheets-Sheet 4 ,5. HinmATTORNEYS.

Oct. 28, 1941. B. HINKS ELECTRIC SWITCH Filed Dec. 14, 1939 5Sheets-Sheet 5 IIVVEIVTOR.

Patented Oct. 28, 1941 ELECTRIC SWITCH Bernard Hinks, Willenhall,England Application December 14, 1939, Serial No. 309,284 In GreatBritain December 22, 1938 7 Claims.

This invention relates to electro-magnetically operated switches of thetype in which the movable contact carrying member is carried by themovable member of an electromagnet which may be the plunger of asolenoid or an armature, and which closes the movable contact member onthe fixed contact carrying member when the magnet is energised.

An object of the present invention is to construct a switch in which themovable contact carrying member when moving from one set of contactswill automatically engage in an eflicient manner. another set ofcontacts. A further object of the present invention isto eflect anautomatic change over from one set of contacts closing one circuit toanother set of contacts closing another circuit after an interval oftime.

In order that the invention may be clearly understood and readilycarried into effect, reference may be had to the accompanying drawingson which- Figure 1 is a front elevation of a switch constructedaccording to this invention, the switch being shown in the oil position.

Figure 2 is an underside plan view of Figure 1 but showing the switchclosed in the star position.

Figure 3 is a diagrammatic arrangement of the switch as shown in Figures1 and 2, the switch being in the off position.

Figure 4 is a similar view of Figure 3, showing the switch closed in thestar position.

Figure 5 is a view of a switch, as shown by Figure 3, in the "deltaposition.

Figure 6 is a diagrammatic arrangement of a modified form of switch andcircuit with the switch in the off position.

Figure 7 is the arrangement shown by Figure 6 with the switch inposition with an auto-transformer in circuit and supplying a current atreduced voltage to the motor.

Figure 8 is the arrangement shown by Figure 6 showing the switch inposition with the autotransformer disconnected.

Figure 9 is a side elevation of a modified form of switch.

Figure 10 is a plan of the switch shown by Figure 9.

Figure 11 is a sectional elevation, the section being taken on lineXIV-XIV of Figure 10.

Fig. 12 is a circuit diagram for the switch shown in Figs. 9, 10 and 11,the switch being shown in the off position.

Fig. 13 is a circuit diagram for the switch shown in Figs. 9, 10 and 11,the primary resistance being in circuit.

Fig. 14 is a. circuit diagram for the switch shown in Figs. 9, 10 and11, the resistance being cut out.

According to a convenient embodiment of this invention, as shown byFigures 1 to 5 the switch is adapted to automatically change over fromthe star to the delta" circuit of an electric motor. The magnetcomprises three limbs I I having the windings 'III on the centre limb.The fixed contact carrying member I'Ia is supported by theelectro-magnet and the armature 2 of the electro-magnet is supported bythe links 5 which pivot on fixed spindles la, the spindles 4b fixed tothe armature 2 being mounted in slots in the links 5. The armature 2 isthus supported by the links 5 when the switch is in the oil position,but the armature is free to rise when in any laterally adjustedposition. The fixed contact carrying member Ila carries three sets ofstar contacts 28 and delta contacts 3|. The moving contact carryingmember I, carrying three sets of blades 29, is fixed to the armature bythe connecting pieces 3. The frame Ila fixed to the electro-magnetcarries the thermostatic switch I4 and the automatic change over switchI1 is also mounted on the fixed frame IIa. When the switch is in the offposition each spindle 4b lies to one side of the pointed portion of aguide member I, so that when the armature rises the spindle will beguided by the side Ia of the members I (see Figure 4). The spring 8normally retains the movable contact carrying member in this position.When the armature is moved laterally to the right and is then lifted itwill pass up between the side lb of the guide, and the fixed framemember He on the left hand side of the switch (see Figure 5).

The operation of the switch is as follows: The moving switch member I onthe armature 2, is held a distance over with the spindle 4b to one sideof the guides I, towards the star contacts 28, by means of the spring 8.When the start button 9 is pressed (Figure 4) the coil III circuit isnow completed by the current passing through the leads A, B, C, D, and Eto L3 to contacts 3IA and this magnetises the three limbed member I I,and attracts the armature which tends to rise vertically and when thearmature has moved a small. distance vertically the spindles lb willstrike against the bottom curved portions of the guides I which willmove the armature 2 and switch the moving contact carrying member I overtowards the star contacts 28 and 28a until the switch blades 28 aredirectly under the fixed contacts 28 and 28a, the spindles 4b will nowpass on one side 01' the guide 1. The switch blades 29 will clme on thefixed contacts 28 and 28a and so connect the motor windings in starFigure 2 and Figure 4 shows the switch in this position. When the switchis in this position, the button 9 is released and this springs back. Thecurrent will now pass from the lead to F, H, G, D, E, to L3. A secondaryvoltage is now induced into the secondary coil l which will cause alarge current to pass through the lead H, l4, G, D, E, to L3, throughthe switch blade and the retaining blade 40, Figures 2 and 4, and thelead K. The blade 40 lies under a blade 29 and presses on the respectivecontact L3, when the blade 29 presses on its respective contact. Whenthe switch has been in this position for about 10 seconds by which timethe motor should have reached approximately full speed, the thermalstrip |4 should have become heated by the secondary current passingthrough this which causes this to distort and so break the circuit ofthe coil l0 and when the armature tends to fall the thermal switchcontacts M will be opened further by means of the member 6 relieving thepressure from the thermal switch and so giving a quick break of thethermal switch. When the armature is falling it will be caught by theslotted members}, but by means of momentum of the armature 2 and theswitch member I attached thereto when falling, such member will swingover and the member will strike the automatic changeover switch i1(Figure 5) to close the coil circuit again and the current will passthrough A, B, C, F, M, contacts ||E to L3 and cause the armature to riseagain, but this time 'it will do so by being guided by the other side ofthe guides 1, and the switch blades 29 will close on to the fixedcontacts 3| and 3|a as shown by Figure 5. The motor will now beconnected in delta. The spindles 4b are alternately guided between aguide I and a frame member Ho. The spring 6 assists in the changeovermovement. The thermal switch I4 is only in series with one of theretaining contacts l3 and the said secondary thermal switch circuit iscompleted when the contactor is in the star position. There are tworetaining contacts l3 which are respectively for the star and the deltapositions. The thermal switch |4 acts as the retaining switch when theswitch is in the star position, current passing from L2, A, l0, B,contacts 9a, C, F, H, 8, D, E to L3. The autochangeover switch acts asthe retaining switch when the switch is in the delta position, currentpassing from L2, A, III, B, contacts 9a, C, F, M, H, E to L3. Thesecondary coil I5 is switched ofi when the contactor is in the deltaposition.

In lieu of utilizing a star and delta arrangement of circuits anauto-transformer is utilised for supplying current at reduced voltagewhen starting up a motor. A convenient embodiment of such an arrangementis shown by Figures 6, 7 and 8. The switch is substantially the same asthat shown by Figures 3 to 5 except that it is adapted to cut out orinclude an autotransformer of known type in the circuit in accordancewith the position of the switch when in the on position. In thisconstruction each pair of switch blades comprises a long blade 29a and ashort blade 29b. When the switchis in the position shown by Figure 10the-short blade and the long blade bridge the contacts, respectively, 62and 33 and include the auto-transformer 34 into the circuit. When theswitch is in the position shown by Figure 11, the long blade 25a bridgesthe contacts 35 and cuts out the autotransformer and allows the currentat full voltage to pass to the motor. The circuits except for thecutting out or putting in the auto-transformer insteadof having thestar" and delta circuits, are as described with reference to Figures 3to 5. In all the drawings the main leads are indicated by Ll, L2 and L3and the motor leads by Ml, M2 and M3. The auto-transformer is of theknown type.

In lieu of the armature of the electro-magnet being mounted to movelaterally with the movable switch such armature may C01 iprise theplunger of a solenoid, the movable switch member being mounted to movelaterally thereon such an arrangement is shown by Figures 9, 10 and 11.The plunger of the solenoid coil 4| carries the guide bar 42 whichslides on the fixed bolts 43, the .bolts being fixed to the framemembers 44 fastened to the switch casing. The frame 45 is fixed to thebolts 43. The movable switch member 46 carrying the contact blades orbridge contacts 41 is attached to the plunger 40 by means of the links46 so that the switch member 46 can bodily swing laterallyin relation tothe solenoid. The switch member 46 is normally held in one position bythe weight bar 49 which rests on the bar 42 and in this position theswitch member 46 is in position, when the solenoid is energised for thebridge contacts to engage the fixed contacts 50 of the fixed contactmember on the frame 45 to include the primary resistances 5| into thecircuit. The automatic action of the switch is similar to that describedwith reference to Figures 6, '7 and 8. The thermostatic switch bar 5|ais closed on the contact 52 by the projection 53 and after an intervalof time, the thermostatic switch breaks and deenergises the solenoid.The plunger with the switch member 46 is opened by the springs 54 andwhen the switch member 46 reaches the limit of its outward movement themomentum of the weight bar 49 causes the switch member to swing over andclose the spring blade switch contact 55 against the contact 56 andenergise the solenoid. This causes the plunger to be attracted to movethe switch member into the on" position with the bridge contacts 41engaging the fixed contacts 56. The fixed contacts 56 are separated bythe insulating walls 58. 59 are the retaining switch contacts whichcoact with the spring arm contact 66 on the switch member 46. The switcharm 55 is located in a slot in the member 6| carried by the switchmember 46, to

prevent movement of the arm 55 when in the position shown by Figure 14.The spring blade contact 55 is fixed at one end to the fixed contactcarrying member and near its other end it passes through the slot in themember 6|. The spring blade contact therefore moves laterally with themovable contact carrying member 46 and the said slot permits the member6| to slide in relation to the contact 55. The switch contacts 55, 56,

remain pressed together whilst the main switch is closed. The contact 56is at its inner end connected to the fixed contact carrying member. Theswitch is guided into the correct position by the guide members 62 and63 which coact respectively with the projection 64 and a bridge contactblade 41. In the position shown by Figure 9, the blade 41 will co-actwith the inclined upper edges of the. guide members position the movablecontact member, if necessary, when attracted to the fixed contact carry-62, 66 to correctly ing member. When the movable contact carrying memberis swung over, the projection 64 will then be in a similar position toco-act with the said inclined upper edges of the guide members 62, 63 ifnecessary. The circuit diagrams of Figures 12, 13 and 14 are exactly thesame as that shown by Figures 3 to except that the contacts 50 connectedrespectively to the leads from the mains Ll, L2, L3 and the leads to themotor- Ml, M2, M3, are substituted for the contacts 28a, 31a, from themains and the contacts 28 and 3| to the motor, to adjust the switch froma stardelta arrangement to an arrangement in which a primary resistanceis put in or cut out.

I claim:

1. An electro-magnetically operated switch comprising anelectro-magnetic device, a movable contact carrying switch memberattached to'the movable member of the electro-magnetic device andsupported on pivoted links so that when in the oil position it iscapable of swinging laterally, a row of bridge contacts carried by saidmovable switch members a fixed contact carrying member having contactswhich can be selectively bridged to complete either of two electriccircuits the movable switch being normally positioned so that whenattracted by the electromagnetic device it will bridge the contacts ofone circuit, a thermostatic switch for breaking the circuit of theelectro-magnet to cause the movable contact member to move into the offposition, means for causing the movable contact member to swing overwhen in the ofi position into position for completing a second circuit,and a switch operated by the said swinging over of the movable contactmember for energising the electro-magnet and moving the switch memberinto position for closing the said second circuit.

2. An electric switch as claimed in claim 1, in which the automaticmeans for swinging over the movable contact member when in the offposition comprises a Weight pivoted to the said pivoted links.

3. An electric switch as claimed in claim 1, in which the current forpassing through the thermostatic switch is induced by the main coil ofthe electr c-magnet.

4. An electric switch as claimed in claim 1, in which the thermostaticswitch is closed by a projection on the movable switch "contact carryingmember when moved into the closed position.

5. An electromagnetically operated selecting switch, comprising anelectro-magnetic device, a movable contact carrying switch memberattached to the movable member of the electromagnetic device, aplurality of parallel bridge contacts carried by the said movable switchmember, a fixed contact carrying member, and means for mounting the saidmovable switch member so that it automatically moves in a lateraldirection when moving from one contacting position to place such memberinto position for being attracted to contact a second set 01 contactsand a switch which is operated by the lateral movement of the movablecontact carrying; member for energising the electro-magnet to cause themovable contact carrying member to move to contact such second set ofcontacts.

6. An electro-magnetically operated selecting switch comprising anelectro-magnetic device, a movable contact carrying switch memberattached to the movable member of the electromagnetic device andsupported on pivoted links so that when in the off position it iscapable of swinging laterally, a row of bridge contacts carried by saidmovable switch member, a fixed contact carrying member having contactswhich can be selectively bridged to complete either of two electriccircuits, means for automatically swinging the movable contact carryingmember laterally into position, for being raised into engagement withthe second set of fixed contacts, when moving from one contactingposition and a switch, which is operated by contact with the movablecontact carrying member when such member swings laterally, forenergising the electro-magnet to cause the movable contact carryingmember to engage the said second set of contacts.

'7. An electro-magnetically operated selecting v switch, comprising anelectro-magnetic device, a movable contact carrying switch memberattached to the movable member of the electroc-' magnetic device, aplurality of parallel bridge contacts carried by the said movable switchmember, a fixed contact carrying member, and means for mounting the saidmovable switch member so that it automatically moves in a lateraldirection when moving from one contacting position to place such memberinto position for being attracted to contact a second set of contacts, aswitch which is operated by the lateral movement of the movable contactcarrying member for energizing the electro-magnet to cause the movablecontact carrying member to move to contact such second set of contactsand means for de-energizing the said electro-magnet after an interval oftime so that the movable switch member will be free to move from onecontacting position to the other.

BERNARD HINKS.

